1. Field of the Invention
The invention relates to a mobile container for goods transport by road such as a semi-trailer or trailer.
2. Description of the Prior Art
Semi-trailer and trailers for transporting bulk goods such as for instance potatoes, onions, granulates and so on with a built-in unloading system are known. Such trailers are also referred to as potato trailers and contain a conveyor belt placed under the cargo space for discharging goods poured into the cargo space via the opened top side. The design of existing trailers and semi-trailers is based on a steel construction supported by a chassis likewise of steel. The side walls and sloping partitions of the cargo space are manufactured from steel, aluminium/PUR sandwich and/or multi-ply. The design of these semi-trailers and trailers has not changed, or hardly so, in twenty-five years.
The object of the present invention is to provide an improved mobile container such as a semi-trailer or trailer with a built-in unloading system which possesses both the transport volume and the functionality of the existing semi-trailers and trailers but which has a lower own weight. It is also an object to provide a mobile container which is relatively simple to assemble.
The invention provides for this purpose a mobile container for goods transport by road such as a semi-trailer or trailer, comprising two standing side walls which enclose on a longitudinal side a converging discharge channel, two end walls connected to the side walls, a conveyor connecting onto the discharge channel for discharge of products, a substructure with at least one wheel pair, and coupling means for connecting the mobile container to a tractor vehicle, wherein at least the side walls are manufactured from a plastic and the assembled side walls and end walls form a self-supporting construction. The self-supporting construction of side walls and end walls, which together form the cargo space, can be realized when the walls are manufactured from plastic, preferably a fibre-reinforced plastic. A very significant advantage of the self-supporting plastic cargo space is that a steel construction such as is applied in the existing semi-trailers and trailers becomes unnecessary. In addition, the chassis can also take a less heavy form than in the existing semi-trailers and trailers (or even be omitted). These various aspects result in a possible weight reduction of more than thirty percent. The result hereof is that the mobile container according to the invention is energy-saving relative to existing semi-trailers and trailers. The loading capacity is also greater. The plastic walls have the additional advantage that they are easy to clean and do not oxidize. A further advantage is that the walls can be manufactured such that they can be assembled in simple manner without much skill or time being necessary for this purpose. The production cost of the mobile container according to the invention can hereby also remain limited. The plastic walls are moreover thermally insulating, which can prevent freezing of the load at low temperatures.
Connecting panels engaging over a determined length onto the side walls are preferably placed between the side walls. Since the semi-trailers and trailers can have a length in the order of magnitude of 10-15 metres, it is necessary to try and find possible ways of increasing the rigidity of the construction. Placing of one or more connecting panels in the cargo space achieves this greater stiffness. In order to prevent excessive local loads on the plastic side walls, the panels engage on the side walls over a determined length. The forces exerted on a wall are thus distributed over a greater length. The connecting panels can for instance be manufactured from plastic-coated, waterproof multi-ply but it is recommended to also manufacture the connecting panels from plastic such as fibre-reinforced plastic. The advantages of water-tightness, corrosion-resistance, great strength, easy cleaning and insulation apply here also.
The conveyor is preferably formed by an endless belt conveyor and a protective hood is preferably arranged between the standing side walls at a distance from the discharge channel. Potatoes, onions, granulates and so on can be discharged from the cargo space by moving the belt conveyor. Since the belt conveyor is placed at the bottom of the cargo space, new product will continually be supplied from the cargo space until it is has been completely emptied. When the belt conveyor is at a standstill it forms the stationary underside of the cargo space and product will not be able to escape via the underside of the cargo space. In order to prevent excessive forces being exerted on the belt conveyor, a protective hood is placed at a distance above the belt conveyor. The protective hood is preferably elongate and the longitudinal sides of the protective hood are located closer to the discharge channel than the part of the protective hood located between the longitudinal sides. When the cargo space is filled with a larger quantity of products, some of these products will support on the protective hood, which limits the pressure exerted on the belt conveyor. In order to prevent products remaining behind on the protective hood during emptying of the cargo space, the hood is formed such that it is provided with one or two inclining sides, whereby the products lying on the protective hood will slide downward along the protective hood during emptying of the cargo space. The protective hood can be manufactured from wood but it is recommended that the protective hood be manufactured from plastic such as for instance fibre-reinforced plastic. The advantages of using plastic have already been described above, to which can be further added that, in contrast to when wood is used, no splinters can be left behind in the transported product.
At least one of the end sides is preferably provided with an opening at the height of the conveyor for passage of discharged goods or products. It is also possible to provide one of the end sides with recesses for accommodating operating means of the container. The discharge opening is required for passage out of the cargo space of goods discharged by the conveyor. In order to prevent goods or products passing through the opening in uncontrolled manner, the opening can be provided with a closing device such as for instance a slide or a door. For an improved finishing of the mobile container, one or more operating means can be integrated into one of the end sides. It is also possible to arrange storage space in one of the end sides or to create a space for access by an operative. Yet another variant is to give an end side a streamlined form so that the air resistance of the mobile container is limited during transport. This can all be realized very effectively by means of an end side manufactured from plastic, preferably fibre-reinforced plastic. In addition to the great design freedom of this material, it also provides the container with the necessary sturdiness.
In yet another preferred embodiment the side walls, end walls, panels and supports of the protective hood are connected such that they enclose rounded corners. This assembly is possible for instance using epoxy with glass fibre tape. The rounded corners enable easy cleaning of the mobile container.
The endless belt conveyor is preferably supported by at least one wedge-shaped supporting member. Such a wedge-shaped supporting member can also be manufactured from plastic and enables good support of the belt conveyor without this entailing a construction element on which dirt, for instance sand, clay and so on, can accumulate.